Hi all, had a question! I am what might be called a casual Trekkie; I have watched pretty much every series and movie I could lay hands on, and TOS was a major part of my childhood, but despite a love of the franchise I am not "in the know" about some of the more technical or arcane details of the universe.

Recently I have started in on Voyager for the first time. While I will decline to comment what I think of the writing, something confused me. The USS Voyager on multiple occasions reenters and exits the atmosphere of M-class planets with a fair amount of indiscretion, something I hadn't thought possible! I had always been of the assumption that starships only reentered in emergency situations- And were more or less worthless once in the atmosphere. So can someone elaborate for me: Are many Federation ships capable of this? Or was it specific to that class of vessel?

In the TOS episode "Tomorrow is Yesterday" (which I just watched today by coincidence), the Enterprise appears within the atmosphere of 1940's Earth. It is chased by a jet. Fun times ensue.

In the early films, the Bird of Prey lands quite often.

So Voyager wasn't the first show to have that in it. Voyager is meant to be a smaller ship than most, it's supposed to be able to do stuff like that. I think the shields they have let them do a little handwaving to neglect atmospheric friction and such.

In the TOS episode "Tomorrow is Yesterday" (which I just watched today by coincidence), the Enterprise appears within the atmosphere of 1940's Earth. It is chased by a jet. Fun times ensue.

In the early films, the Bird of Prey lands quite often.

So Voyager wasn't the first show to have that in it. Voyager is meant to be a smaller ship than most, it's supposed to be able to do stuff like that. I think the shields they have let them do a little handwaving to neglect atmospheric friction and such.

Ah! Well, guess I had forgotten the other times it has been done then. Clearly I need to go rewatch TOS and TNG!

HOW are they maneuvering in the atmosphere? The amount of force output by their thrusters would have to be ridiculously high to keep them up.

Well in Star Trek Generations they clearly could not stay up in the air, but in Voyager was one of the most advanced starships of its time. This is said a couple of times throughout the series also in the second season on the episode 38ís ( I think) Janeway talks about how the ship was designed to be able to land on planets.

This is probably why the ship can use maneuvering thrusters in the atmosphere.

I think the crash in Generations was very much a matter of power. Generations wasn't the Enterprise D's only atmospheric entry. In The Arsenal of Freedom it was able to enter and then leave an atmosphere while the ship wasn't separated, i.e. it still had its warp core. Without the warp core connected, the saucer can't really do much. It can limp around at impulse, but generally it's stuck siting around and waiting for the stardrive or a tow to come pick it up.

One of the reasons that ships need the crazy power levels the warp core puts out is that half of the stuff they do is explained by bending space and altering fundamental laws of motion around them. The Bird of Prey in ST IV created less of a thrust wash than a small helicopter does when it took off, so it appears their ability to disregard physics still works in an atmosphere. In Aresenal, the Enterprise had its full capabilities and was able to exit the atmosphere again. In Generations it didn't, so it was doomed as soon as the explosion pushed them into an orbit that intersected the planet (assuming they didn't disconnect already in a doomed orbit).

I would also say they have some anti-grav abilities like the anti-grav sleds. How do you think shuttles do it without creating wash.

Voyager too I believe reconfigured their thruster for atmospheric use. I believe Paris stated something to this effect. Also it would not be too far flung to expect shields are used to reduce atmospheric drag effects.

Another thing some might note is that the RCS thrusters on Voyager we large for the ship size, you know the orange/brown things around the saucer, 4 of them. This would add the perception of increased power for atmo maneuvering.

With the Ent-D Saucer in Generations. remember they had just been blown to pieces by a BoP, who knows which systems had failed. Additionally it was actually the explosion of the star drive which pushed them into an uncontrollable descent to the planet. Under control the saucer may have survived, but the extra speed and the angle (coupled with lack of power) caused the crash... Troi should have flown in the other direction

The NX-01 also did atmsopheric entry at least once that I can remember, though it was much smaller than the later ships. And impulse engines have demonstrated the ability to move ships at a significant fraction of lightspeed, crossing star systems in a few hours, and manage to maneuver truly huge ships with relative grace. As such I imagine that the thrust output is something staggering, and that really the limitation on operating in-atmosphere is more a question of structural forces than anything else. Things like giant nacelles hanging off of slender pylons at weird angles probably would be subject to absurd stresses inside an atmosphere, whereas something like Voyager was a lot more compact and structurally sound than a Galaxy. Of course its all still super-science and a sharp turn in space still should have had insane shearing forces, but this is the same sort of sci-fi where constant thrust equals constant velocity.

Additionally it was actually the explosion of the star drive which pushed them into an uncontrollable descent to the planet.

Not the star, it was the warp core breach when the stardrive section blew up before they reached safe range. The supernova destroyed them (and the entire planet for that matter) shortly after the crash, so when Picard stopped the supernova from happening at all, the Enterprise still crashed.

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Of course its all still super-science and a sharp turn in space still should have had insane shearing forces, but this is the same sort of sci-fi where constant thrust equals constant velocity.

One of the most commonly mentioned bits of tech in the shows is inertial dampeners. Ships in Star Trek can negate inertia, which does a lot of things: It keeps the crew from being converted into a viscous smear against the rear bulkheads during warp acceleration, prevents shearing force in a turn, reduces lethal effect to dramatic effect on weapon strikes, and it's also why ships lose speed when they lose thrust - inertia's what would keep them going.